1. Field of the Invention
The present invention relates to a fuse box, a fuse, and a fuse block to be installed in a vehicle which is a moving body.
2. Description of the Related Art
In the vehicle as the moving body, there are various transmission lines for transmitting electric power, signals and so on, such as busbars contained in a connection box, such as a junction block, a relay box, a fuse block, terminals of electrical connector, etc.
Heretofore, a voltage of the electric power for use in the transmission lines has been mainly 12V in the case of a general passenger automobile, and has been 12Vxc3x972=24V in the case of a large vehicle, such as a bus, a truck, etc. However, in view of recent requests for an increase in driving efficiency of loads and for driving at most appropriate efficiency per the load, it is now being considered to employ a power system capable of supplying electric power having higher voltage than before, such as 36V, for example.
In the above described transmission lines, there have been used fuse blocks in which a number of detachable fuses are disposed for protecting electric circuits of various types of electric equipment from breakdown. Since the fuse block may sometimes include relays and busbars, the fuse block is also called a relay box or a junction block, or generally called a connection box. In this specification, the fuse block, relay box, junction box and connection box will be hereinafter called the fuse block, in general.
In the vehicle in which employment of the power system capable of supplying electric power having higher voltage than before, as described above, is intended, it is considered to employ a fuse block provided with a first fuse (hereinafter referred to as high voltage fuse) and a fuse box having a first mounting part to which the high voltage fuse can be detachably mounted. The fuse block is supplied with the electric power having a first voltage, such as 36V, higher than 32V which has been conventionally employed. The high voltage fuse is adapted to be fused when the electric power above an amperage corresponding to the first voltage has been supplied and interrupts the supply of the power to the various loads.
Meanwhile, in the vehicle installed with the conventional power system, which supplies electric power of 12V and 24V, a fuse block provided with a second fuse (hereinafter referred to as a rated voltage fuse) and a fuse box having a second mounting part to which the rated voltage fuse can be detachably mounted is employed. The above described rated voltage fuse is supplied with electric power having a second voltage, such as 12V and 24V, which is lower than the aforesaid first voltage. The rated voltage fuse is adapted to be fused when the electric power above an amperage corresponding to the second voltage has been supplied and interrupts the supply of the power to the various loads.
The fuse block, fuse box and fuse, which have been heretofore employed, are constructed in such a manner that the rated voltage fuse can be also mounted to the first mounting part.
For this reason, when assembling the fuse block to be installed in the vehicle in which employment of the power system capable of supplying the power having higher voltage than before is intended, there has been such a fear that the rated voltage fuse may be mounted to the first mounting part by mistake.
If the rated voltage fuse has been mounted to the first mounting part, such an inconvenience may occur that the rated voltage fuse may be fused and the loads may not be supplied with the power, even though the voltage of the power which is supplied to the loads connected to the first mounting part is normal. In some cases, a fusible body of the rated voltage fuse may be blown off due to the high amperage, and terminals of the rated voltage fuse may be short circuited to each other.
When the terminals of the rated voltage fuse have been short circuited to each other, it is feared that the rated voltage fuse and the fuse block may be melted down and broken. In the worst case, the loads connected to the first mounting part may be damaged.
As described above, in the conventional structure of the fuse block, fuse box and fuse, in a case where the rated voltage fuse for conventional use has been mounted to the mounting part to be supplied with the power having the first voltage over 32V, it has been feared that the loads may not be supplied with the power even though the voltage of the power supplied to the loads is normal, or that the fuse block and the fuse itself may be melted and broken.
In view of the above, an object of the invention is to provide a fuse box, a fuse, and a fuse block which can prevent a fuse adapted to be fused at an amperage corresponding to a voltage which has been conventionally used from being mounted to the mounting part which is supplied with electric power having higher voltage than before.
In order to solve the above described problems and attain the object, according to a first aspect of the present invention, there is provided a fuse box comprising a box body formed in a box-like shape, and at least one first mounting part adapted to contain a pair of first receiving terminals which are arranged in parallel to each other, one of the first receiving terminals being supplied with electric power having a first voltage higher than 32V, wherein the first mounting part includes blocking means for preventing a rated voltage fuse which is so adapted as to fuse at an amperage corresponding to a second voltage which is lower than the first voltage from being mounted thereto.
In the fuse box according to the first aspect, the blocking means block the rated voltage fuse from being mounted to the first mounting part which contains the first receiving terminals and is supplied with the electric power having the first voltage higher than 32V. Accordingly, the rated voltage fuse can be prevented from being mounted to the first mounting part.
In the fuse box according to a second aspect of the present invention, the first mounting part is formed by denting a surface of the box body, including an opening which opens in the surface of the box body and a plurality of surrounding walls continued from peripheral edges of the opening, and the blocking means include projections which are projected from the surrounding walls into the first mounting part.
In the fuse box according to the second aspect, because the blocking means are the projections projected from the surrounding walls which constitute the first mounting part, the projections are abutted against the rated voltage fuse when the rated voltage fuse is mounted to the first mounting part. Thus, the rated voltage fuse can be more reliably prevented from being mounted to the first mounting part.
In the fuse box according to a third aspect of the invention, the surrounding walls of the first mounting part include a pair of first surrounding walls which are opposed to each other in a direction in which the first receiving terminals are juxtaposed, and a pair of second surrounding walls which are continued from the first surrounding walls and opposed to each other in a direction intersecting the direction in which the first receiving terminals are juxtaposed, and the projections are formed by projecting from both the first surrounding walls and the second surrounding walls which are adjacent to each other across the first surrounding walls and second surrounding walls.
In the fuse box according to the third aspect, because the projections are projected across the first surrounding walls and the second surrounding walls which constitute the first mounting part, the projections are reliably abutted against the rated voltage fuse when the rated voltage fuse is mounted to the first mounting part. Thus, the rated voltage fuse can be more reliably prevented from being mounted to the first mounting part.
There is further provided, according to a fourth aspect of the present invention, a fuse comprising a pair of connecting terminals arranged in parallel to each other, one of the connecting terminals being capable of supplying electric power having a first voltage higher than 32V, and a housing adapted to receive one end portion of the connecting terminals, wherein the housing includes outer walls forming an outer shell, and recesses formed by denting surfaces of the outer walls.
In the fuse according to the fourth aspect, the housing is provided with the recesses formed by denting the surfaces of the outer walls. Therefore, by providing the mounting part of the fuse with projections, or the like, which will not interfere with the recesses, the rated voltage fuse, which has been conventionally used, can be prevented from being mounted to the mounting part.
In the fuse according to a fifth aspect of the invention, the outer walls of the housing include a pair of first outer walls which are opposed to each other in a direction in which the first connecting terminals are juxtaposed, and a pair of second outer walls which are continued from the first outer walls and opposed to each other in a direction intersecting the direction in which the first connecting terminals are juxtaposed, and the recesses are formed by denting the first outer walls and the second outer walls which are adjacent to each other across the first outer walls and second outer walls.
In the fuse according to the fifth aspect, the housing has the first outer walls and the second outer walls, and the recesses are formed across the first outer walls and the second outer walls. Therefore, by providing the mounting part for the fuse with projections, or the like, which will not interfere with the recesses, the rated voltage fuse, which has been conventionally used, can be prevented from being mounted to the mounting part.
There is further provided, according to a sixth aspect of the present invention, a fuse block comprising a box body formed in a box-like shape and a first mounting part adapted to receive a pair of first receiving terminals which are arranged in parallel to each other, one of the first receiving terminals being supplied with electric power having a first voltage higher than 32V, a second mounting part adapted to receive a pair of second receiving terminals which are arranged in parallel to each other, one of the second receiving terminals being supplied with electric power having a second voltage lower than the first voltage, a first fuse having a pair of first connecting terminals which are arranged in parallel to each other and adapted to be respectively connected to the first receiving terminals, and a first fusible body which is adapted to fuse when the electric power whose amperage is higher than a value corresponding to the first voltage has been supplied, the first fuse being adapted to be detachably mounted to the first mounting part, and a second fuse having a pair of second connecting terminals which are arranged in parallel to each other and adapted to be respectively connected to the second receiving terminals, and a second fusible body which is adapted to fuse when electric power whose amperage is higher than a value corresponding to the second voltage has been supplied, the second fuse being adapted to be detachably mounted to the second mounting part, wherein the first mounting part is formed by denting a surface of the box body, including an opening which opens in the surface of the box body, a plurality of surrounding walls continued from peripheral edges of the opening, and projections which are projected from the surrounding walls into the first mounting part, and the first fuse includes the pair of the first connecting terminals, a housing adapted to receive one end portions of the first connecting terminals and including outer walls forming an outer shell, and recesses which are formed by denting surfaces of the outer walls and may not interfere with the projections.
In the fuse block according to the sixth aspect, the first mounting part is provided with the projections projected from the surrounding walls. Accordingly, the second fuse cannot be mounted to the first mounting part. Meanwhile, the first fuse is provided with the recesses which are dented from the outer walls and may not interfere with the projections. Accordingly, the first fuse can be reliably mounted to the first mounting part.
In the fuse block according to a seventh aspect of the invention, the surrounding walls of the first mounting part include a pair of first surrounding walls which are opposed to each other in a direction in which the first receiving terminals are juxtaposed, and a pair of second surrounding walls which are continued from the first surrounding walls and opposed to each other in a direction intersecting the direction in which the first receiving terminals are juxtaposed, the outer walls of the housing include a pair of first outer walls which are opposed to each other in a direction in which the first connecting terminals are juxtaposed, and a pair of second outer walls which are continued from the first outer walls and opposed to each other in a direction intersecting the direction in which the first connecting terminals are juxtaposed, the projections are formed by projecting from the first surrounding walls and the second surrounding walls which are adjacent to each other across the first surrounding walls and second surrounding walls, and the recesses are formed by recessing the first outer walls and the second outer walls which are adjacent to each other across the first outer walls and the second outer walls.
In the fuse block according to the seventh aspect, the projections are formed across the first surrounding walls and the second surrounding walls adjacent to each other. Therefore, the second fuse can be prevented from being mounted to the first mounting part, and the first fuse can be reliably mounted to the first mounting part.
In the fuse block according to an eighth aspect of the invention, the projections and the recesses come into alignment with each other when the first fuse has been mounted to the first mounting part.
In the fuse box according to the eighth aspect, because the projections and the recesses come into alignment with each other, the first fuse can be more reliably mounted to the first mounting part.